1. Field of the Invention
The present invention relates to an electrical testing device for electrical power extension cords and electrical power tools.
2. Description of Related Art
The maintenance of electrical power extension cords and electrical power tools in a proper and safe operating condition is a problem to which considerable attention need be given. In particular, electrically powered extension cords and tools used at construction or plant sites must be tested for proper wiring conditions daily so as to comply with governmental safety regulations as well as to insure their proper operating condition. In order to determine the proper and safe operating condition of a power tool or power extension cord, it is necessary to perform a number of individual tests. Due to the large number of cords and tools which may be utilized at a construction or plant site, it is necessary that the individual tests be performed as expediently as possible without sacrificing any quality and reliability in the testing procedure.
U.S. Pat. No. 4,859,932, issued on Aug. 22, 1989 to William E. Whitley, describes a multi-function tester. Whitley does not suggest the electrical testing device according to the claimed invention.
U.S. Pat. No. 5,280,251, issued on Jan. 18, 1994 to Christopher E. Strangio, describes a multi-conductor cable tester. Strangio does not suggest the electrical testing device according to the claimed invention.
U.S. Pat. No. 5,285,163, issued on Feb. 8, 1994 to William A. Liotta, describes a hand-held tester which performs both off-line continuity tests and on-line voltage tests for electrical cables and equipment. Liotta does not suggest the electrical testing device according to the claimed invention.
U.S. Pat. No. 5,477,133, issued on Dec. 19, 1995 to Kent L. Earle, describes an electrical test device for testing circuits. Earle does not suggest the electrical testing device according to the claimed invention.
U.S. Pat. No. 5,572,117, issued on Nov. 5, 1996 to Hee Y. Yoon, describes a multi-meter which is capable of measuring a Z-state of an output signal from a thing to be measured, in addition to high and low states thereof. Yoon does not suggest the electrical testing device according to the claimed invention.
U.S. Pat. No. 5,604,439, issued on Feb. 18, 1997 to Clifford L. Walkington et al., describes a tractor/trailer lamp circuit continuity test device. Walkington et al. do not suggest the electrical testing device according to the claimed invention.
U.S. Pat. No. 5,625,285, issued on Apr. 29, 1997 to Larry A. Virgilio, describes a self-contained, plug-in, hand-held device for testing the current carrying ability of the Hot wire and the Safety Ground return of standard AC outlets which have Hot, Neutral, and Ground connections. Virgilio does not suggest the electrical testing device according to the claimed invention.
Australia Patent document number 245,742, published on Feb. 9, 1961, describes a safety device for testing the earth lead and plug earth pin of an electrical appliance. Australia '742 does not suggest the electrical testing device according to the claimed invention.
The abstract and figure of Germany Patent document number 2,828,095, published on Jan. 10, 1980, describes a universal test plug with five contacts and five light emitting diodes (LEDs) on the bottom or front face that give a phase sequence indication. Germany '095 does not suggest the electrical testing device according to the claimed invention.
Great Britain Patent document number 1,587,043, published on Mar. 25, 1981, describes a portable testing device for determining earth leakage, earthing continuity, and open circuit load conditions on an electrical appliance terminated with a three-pin plug. Great Britain '043 does not suggest the electrical testing device according to the claimed invention.
U.S. Pat. No. 4,929,902, issued May 29, 1990, to Nelson, discloses a longline coaxial cable testing device having a transmitter-analyzer unit and a receiving unit. The device uses different size connectors to accommodate different size coaxial cables. The device requires a terminating receiver unit for shorting one end of the coaxial cable. Nelson does not provide a quantitative indication of the capability of the conductor to carry a required amount of current.
U.S. Pat. No. 5,192,912, issued Mar. 9, 1993, to Lemon, discloses a trailer wiring harness tester having a selectable AC/DC power source. Lemon does not provide a quantitative check of extension cords or power tool ground lines.
U.S. Pat. No. 3,723,863, issued Mar. 27, 1973, to Myers, discloses a portable ground continuity tester for checking the ground line of power tools. Myers does not provide a quantitative indication of the capability of the conductors in an extension cord to carry the required amount of current.
U.S. Pat. No. 5,477,152, issued Dec. 19, 1995, to Hayhurst, discloses a device for testing continuity and short circuits in cable. Hayhurst has a plurality of connectors (e.g., BNC, phono, F-type) in pairs electrically connected via the testing circuit for determining line breaks or shorts in a cable coupled between each pair of connectors. Hayhurst does not provide a quantitative indication of the capability of the conductor to carry a required amount of current.
U.S. Pat. No. 5,781,015, issued Jul. 14, 1998, to Duffin, et al., discloses an extension cord having an integral monitoring system for positively indicating the presence of power and current flow in the conductors of an extension cord. Duffin, et al. does not provide a quantitative indication of the capability of the conductor to carry a required amount of current.
Japanese Patent Document No. 06-3398, published Jan. 11, 1994, discloses a multiconductor cable break tester having a pair of cable connectors for coupling a cable under test to the device, and a plurality of LEDs for indicating the continuity of the conductors in the cable. The continuity is determined by moving the cable, placing the connectors under a physical load, and observing the LEDs for indications of a conductor break or discontinuity. Japanese Patent Document No. 06-3398 does not provide a quantitative indication of the capability of the conductor to carry required amount of current.
None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed.